The Office

Unlike the Mass (which is a single occurrence, although repeatable throughout
the day), the Office structures multiple sessions of prayer at set hours
during the day. Also, unlike the Mass which can be traced to direct institution
by Christ, the Office has its origins in more generalized directions for
continuous and watchful prayer (e.g., Ps. 119:164, Mark 13:34-35, Luke
11:2-4, 1 Thess. 5:17), which derive from the Jewish tradition of community
prayer in the synagogue at specific times during the day. As learned from
the Jewish custom, these prayers were at first only for the opening and
closing hours of the day; gradually other fixed or "canonical"
hours were added, and the final form was established by Benedict of Nursia
in the first half of the 6th century. Benedict's Rule lays out
very clearly the times and order of daily prayer, including recitation
of the entire psalter over the course of the week; the Rule also
specifies readings from scriptural and patristic texts at Matins. Since
monks were responsible for the running of Rome's churches during this
and the following century, the monastic office came to form the basis
also for the secular office. These two uses, monastic and secular, remained
the basis for daily prayer in the Western church throughout the Middle
Ages, although --as one would expect-- with considerable local and seasonal
variation.

As originated by Benedict, the office would occupy some four to five
hours of a monk's day; with gradual and sometimes intense elaboration,
the daily office at one point grew to where it was absorbing an astonishing
ten to twelve hours, especially on the most important feasts. Reform of
the Office was, obviously, a frequent refrain in those orders who split
away from traditional Benedictine monasticism.

The eight services, with a highly simplified outline of their times (which
would have varied according to local custom, as well as geographical and
seasonal determination of the amount of daylight available):

Matins

2:30 am

Lauds

5:00

Prime

6:00

Terce

9:00 (the daily Mass usually took place after Terce)

Sext

noon

None

3:00 pm

Vespers

4:30

Compline

6:00

A breviary
unites all the chants and texts needed for the celebration of the Divine
Office. It combines the separate books that
contained prayers (the collectar), Matins lessons (the office
lectionary), chants (antiphonal
and choir psalter), and ordinary chants and
readings (the diurnal). The individual texts may be indicated only by
their incipit. Breviaries are often small portable books, usually smaller
than antiphonals. Breviaries
meant for use in choir can contain musical notation , but those for private
recitation of the Office, which was increasingly common in the later Middle
Ages, are not notated. Some luxurious breviaries are fancifully decorated
but many are modest books devoid of illumination .